A laser direct imaging (LDI) system suitable for recording electrical circuit pattern portions on photosensitive layers of electrical circuit substrates is commercially available from Orbotech Ltd. of Yavne Israel under the name DP-100™.
Among the problems which arise during the manufacture of multi-layered printed circuit boards is that an electrical circuit pattern portion that is recorded on a substrate layer needs to have precise dimensions and needs to be precisely aligned on the substrate layer so that it can be readily combined with electrical circuit pattern portions formed on other substrate layers. The following copending U.S. patent applications describe various systems and methodologies that may be helpful in ensuring that electrical circuit pattern portions recorded on printed circuit board substrates have requisite dimensions and alignment: Ser. Nos. 09/708,160, 09/792,498 and 10/045,651. These are incorporated by reference for their useful background teachings in this regard.
In the manufacture of multi-layered printed circuit boards, a plurality of independent electrical circuit pattern portions are formed on an electrical circuit substrate. Typically, each of the independent pattern portions will be incorporated into a different electrical circuit device. According to one method of printed circuit board manufacture, several substrate layers, each containing an appropriate arrangement of electrical circuit portions, are combined to form a printed circuit board. According to another method of printed circuit board manufacture, several layers of an electrical circuit are built up in sequential layer formation steps on the same electrical circuit substrate core.
During manufacture, process errors and handling can result, inter alia, in a change of dimension, change of shape or change in location, relative to an absolute dimension, shape or location, of the electrical circuit substrate. Such changes may affect one or more electrical circuit portions already formed on the substrate, thus requiring suitable adaptation of subsequently formed electrical circuit portions.